The only "actions" that are counted towards the badge are those done while on the /review page. You can check the numbers in the "Your Review Stats" box on that page.
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chownDec 4 '11 at 16:23

@chown Ah, I think there might be two problems. I see a different view when I go to /review on SO than on other sites, and I didn't quite know exactly what "actioned" really meant. Thanks.
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Bill the LizardDec 4 '11 at 17:16

@Bill: Also, multiple actions on one post don't count, only one per post.
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animuson♦Dec 4 '11 at 17:43

Thanks. It turns out I was working from an incomplete understanding of what "actioned" means. It's probably obvious to anyone paying attention, but for anyone else wondering, you have to take actions from the /review page or they don't count.
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Bill the LizardDec 4 '11 at 17:20

2

@bill not true, a post becomes "reviewed" if you click "review post" or the hyperlink from the /review page. You can act on it anywhere after that
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wafflesDec 4 '11 at 21:44